VOL. II.-PNEUMATICS, ELECTRICITY, MAGNET-

ISM, AND OPTICS.

COMPILED FROM VARIOUS AUTHORITIES.

BY DENISON OLMSTED, A. M.

PROFESSOR OF MATHEMATICS AND NATURAL PHILOSOPHY.

NEW HAVEN:

PUBLISHED BY HEZEKIAH HOWE & CO?

1832.

Entered according to Act of Congress, in the year 1832, by DENISON OLMSTED,

in the Clerk's office, of the District Court of Connecticut.

ADVERTISEMENT.

THE original design of the compiler of this work, was merely to reduce Bridge's Mechanics to such a form and size, as would be adapted to the limited time and opportunities of a class in college. With this view the following changes were made.

1. By printing in a smaller type and more compactly, and retaining such parts only as were deemed most important to the general scholar, the six hundred pages of which the original work consisted, were reduced to one hundred and eighty eight.

2. The most important propositions were more distinctly enunciated, and separated from the context. In order still farther to give them peculiar prominence to the eye of the student, they were marked by the word Theorem.

3. New definitions were supplied, explanatory notes added or interspersed, and occasional extracts from other writers introduced.

4. A number of new problems were added, or substituted; and, in some instances, such as were expressed in the general terms of A, B, &c., were so modified as to be more interesting and practically useful to the young learner.

The impossibility, however, of finding corresponding treatises on the other branches of Natural Philosophy, and the general dissatisfaction which prevailed with Enfield's Institutes, (the work then used as a Text Book,) were urged upon the writer as reasons for completing a full course of the Elements of Natural Philosophy,—a task which he has attempted to fulfil in the work now offered to the public. Although a compilation, merely, according to the terms of agreement with the publisher, was all that the writer felt himself bound to execute, yet the work has approached nearer and nearer to an original composition as it has advanced. Indeed, the greater part of the second volume has been composed anew.

In most of our colleges, within a few years, so many new departments of study have been introduced, that the want of time for the completion of a full and thorough course of scientific studies, is seriously felt. The necessity of making this work extremely concise,